Steerable and flexibly curved probes

ABSTRACT

Steerable and flexibly curved probes are provided, primarily for surgical applications. A probe with flexible distal portion is inserted through an incision or cannula and the flexible distal portion may be selectively bent or steered using a guide wire. The guide wire is extended through the probe on a radially offset axis, and affixed at its distal end to the distal end of the flexible distal portion. The curvature of the nitinol wire is induced by extending or retracting the wire from the proximal end of the flexible distal portion while the distal end of the guide wire remains affixed to the distal end of the probe. The guide wire is activated by a finger-actuated mechanism. A further embodiment is provided in which the guide wire is fixed at both ends of the flexible distal portion of the probe and has a normally curved conformation, and assumes such conformation after insertion through a straight cannula. Other embodiments and applications are similarly disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Application No. 60/887,635 (“Steerable Intraocular Laser”),filed Feb. 1, 2007, and U.S. Provisional Application No. 60/887,921(“Flexible Curved Intraocular Laser Probe”), filed Feb. 2, 2007. Theentire respective disclosures of each of said provisional patentapplications are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns insertable probes, primarily in the surgicalfield, which can be steered or redirected after insertion. Severalembodiments of the invention are in the form of steerable or flexiblycurved microsurgical laser probes for use primarily in ophthalmicsurgery. However, the invention also relates to insertable probesgenerally and has non-medical applications, for example, to non-medicalendoscopy and boroscopy.

2. Background of the Related Art

A wide variety of surgical and diagnostic methods involve the insertionof probes, catheters, endoscopes and other devices into interior spacesand passageways within human or animal organs.

In the ophthalmic field, for example, intraocular laserphotocoagulation, or the process of forming a blood clot in the interiorof the eye using a laser, is performed in many types of surgicalprocedures. Application of laser photocoagulation is commonly done withthe aid of a probe that carries an optical fiber that can direct thelaser light. The fiber optic directs the laser energy from the lasersource into the eye to the site of the coagulation. A typical prior artlaser probe is shown in FIG. 1. Prior art probe 101 has a straightintraocular section 102 made from a straight metal sleeve. The metalsleeve covers the fiber optic 103 to protect the fiber optic 103. Theguided laser output 104 exits the distal end 105 of the fiber optic 103and impinges upon the coagulation site 106. Blood at the coagulationsite 106 is coagulated by the energy transferred to that site by guidedlaser output 104.

Although easy to manufacture, there are shortcomings associated with theprior art laser probe. Surgical requirements limit how a laser probe 101of the prior art can be inserted into the eye. When a laser probe 101 isinserted around insertion site 107 of the eye, the guided output 104from the laser probe 101 cannot reach far periphery area 108 of the eyebecause the crystalline lens 109 of the eye blocks the range of motionof the laser probe 101. In fact, the furthest peripheral point towardthe lens that the prior art laser probe 101 can reach is coagulationsite 106 as shown in FIG. 1, when the probe comes into contact with thecrystalline lens 109 at contact point 110. In addition to thislimitation in reach, the laser probe 101 has an additional limitationthat when the laser probe 101 is inserted at angle 111 as shown in FIG.1, the intensity of the guided laser output 104 is reduced atcoagulation site 106 because the guided laser output 104 is impinging onthe coagulation site at a non-perpendicular angle 111. This reduction inintensity in turn reduces the effectiveness of the prior art laser probe101. If, on the other hand, the guided laser output 104 could be made tobe normal to the coagulation site 106, then the intensity of the guidedlaser output 104 would be at its maximum (for any given distance betweendistal end 105 and coagulation site 106) and the laser probe would bemore effective.

In attempts to overcome these shortcomings, several variations of themetal sleeve laser probe of the prior art are in the field. There arecurved laser probes made with a fixed and curved metal outer sleeve.These types of probes solve the problem of letting its guided laseroutput reach the far periphery of the eye. But unfortunately theseprobes can be used only with great difficulty in modern small incisionvitrectomy surgery using cannulae. The cannulae used in vitrectomysurgery are typically straight cannulae that limit the passage of anycurved probe or instrument. Even if the surgeon manages to force acurved laser probe through the cannula, the removal of the curved probefrom the eye often causes the undesired effect of the cannula beingremoved from the eye as well. Another variation of the prior art laserprobe uses a straight metal sleeve surrounding a fiber optic containedin a second metal tube having a curved contour. During surgery the outersleeve is retracted allowing the inner sleeve to adopt a curved contour.But again, this type of laser probe is difficult to manipulate duringsurgery. There are additional shortcomings with this type of laserprobe. For one example, it can curve in only one direction. For a secondexample, to remove the probe from the eye, the second metal tube must bemanually straightened, necessitating awkward motions on the part of thesurgeon and placing the eye at risk of inadvertent injury.

Another shortcoming common to all three types of prior art laser probesdescribed above is that all of these laser probes employ a rigid metalouter sleeve that is potentially traumatic to delicate intraocularstructures. Inadvertent contact with the lens or retina in particularcan lead to serious physiological consequences.

Accordingly, the current state of intraocular laser probes is suboptimaland there is a need for a laser probe in which the angle or curvature ofthe optical fiber can be easily and quickly varied by the surgeon atwill. Moreover, a device that solves the problems described above wouldhave applicability in many other types of surgical and diagnosticprocedures which involve the insertion of probes and the like intointerior spaces and passageways within body organs of humans or animals,as well as corresponding non-medical mechanical applications.

SUMMARY OF THE INVENTION

The present invention addresses the above-noted shortcomings in theprior art by providing a steerable or flexibly curved instrument. In oneembodiment, the instrument may be a probe that can be straight in itsalignment while being inserted, such as through a cannula, but afterinsertion can adopt a curved shape upon manipulation by the operator soas to afford better access to interior areas that were not easilyreached by a prior art devices.

In one embodiment, the probe comprises a tubular member providing animplement, for example, a surgical or diagnostic tool, at the distal endthereof. The tubular member is flexible along its axis and has at leastone axial bore. A guide wire is disposed within the bore, such that theaxis of the guide wire is radially offset from the axis of the tubularmember. The guide wire is affixed to the tubular member at or near itsdistal end. The guide wire may be of a type, such as a nitinol wire,normally having a first lengthwise conformation (e.g., straight), andthe property whereby it tends to return to said first lengthwiseconformation after being deformed therefrom. In one embodiment, a fiberoptic guiding the output of a laser source is also housed in the tubularmember, so that the laser light exits the steerable probe at its distalend. Any other suitably sized implements, such as tools for performing asurgical operation, electrodes, sensors, imaging elements, etc., may beprovided within and/or at the distal end of the probe; the probe itselfmay be adapted to hold the desired implement at or near its distal end.

Since the guide wire is affixed to or near the distal end of the probe,retracting the guide wire within the bore tends to make the probecurvedly deform in a transverse direction, such that (as a result of theradial offset of the guide wire as it runs through the tubular member)the guide wire will be situated on the inside of the radius of curvatureof the probe (where the circumference is shorter). Similarly, extendingthe guide wire will tend to make the probe curvedly deform transverselyin the opposite direction, i.e., such that the guide wire will besituated on the outside of the radius of curvature of the probe (wherethe circumference is longer). Thus, acting on the guide wire to extendor retract it in the bore provides a means of “steering” the probe.

In some embodiments, the radial offset of the guide wire within thetubular member is provided by having a separate, offset bore within thetubular member, for the guide wire. In other embodiments (for examplesmall-gauge embodiments), the guide wire is radially offset but housedin the same bore as the optical fiber or other instrumentation fibers,cables or components (if any).

In other embodiments, a finger-actuated control within the handleactuates the slidable movement of the guide wire relative to the bore ofthe probe. Several possible embodiments of such a control areillustrated. In addition, various handle components are provided to holdthe instrument and house the actuation controls.

In a further embodiment, the guide wire is provided in a normally curved(as opposed to straight) configuration, and is not slidably movable, butrather is fixed at both ends of the flexible tubular member. In thisembodiment, the probe may, for example, be inserted through a straightcannula, by using minimal insertion force to transiently straighten it,and will then assume its naturally curved conformation after insertion,thus providing many of the advantages of the invention with a simplerapparatus than the other embodiments.

Further features and embodiments of the invention are illustrated by theaccompanying drawings and further explained in the detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a prior art laser probe whileperforming a coagulation operation in the eye.

FIGS. 2A-C are three side sectional views of an embodiment of a probe inaccordance with the present invention.

FIGS. 3A-B are cross-sectional views taken perpendicular to the axis ofthe tubular member of two different embodiments of a probe in accordancewith the present invention.

FIG. 4 is a side elevational view of an embodiment of a probe inaccordance with the present invention coupled with an embodiment of asurgical handle in accordance with the present invention.

FIGS. 5A-B are side sectional views of a probe with a surgical handle,similar to the instrument shown in FIG. 4, and having a slidablefinger-operated control.

FIGS. 5C-D are axial and transverse cross-sectional views, respectively,of the housing assembly within the finger-operated control shown inFIGS. 5A-B.

FIGS. 5E-F and 5G-H are, respectively, elevational views of twoadditional embodiments of a probe instrument having a finger-operatedcontrol, representing (in FIGS. 5E-F) a lever-based embodiment employingsubstantially the same housing assembly as in FIGS. 5A-B, and (in FIGS.5G-H) an embodiment that has a different construction of the control.

FIG. 6 is a side sectional view of an alternate embodiment of a probe inaccordance with the present invention.

FIG. 7 is a side sectional view of a probe assembly comprising a handleand a probe as shown in FIG. 6.

DETAILED DESCRIPTION

The following is a description of several embodiments of various aspectsof the invention. These embodiments are illustrative only. The inventionis limited only by the scope of the claims that are appended hereto, andis by no means limited to particular examples described below.

The present invention is useful for many purposes. The anticipated fieldof use is generally referred to herein as “surgery.” However, the terms“surgery” and “surgical” should be understood in a broad sense, as alsoincluding diagnostic methods carried out internally, and relatedinstruments, as well as minimally invasive procedures and instruments,or those employed through a small incision, such as in connection withcatheterization and endoscopy. In addition, the invention is alsoadaptable to non-medical applications, such as non-medical endoscopy andboroscopy, and the use of the term “surgical” or like medical-relatedterms should not be understood as limiting the scope of the invention tomedical applications.

FIGS. 2A-C show side sectional views of an embodiment of a probe of thepresent invention and its steering action. As shown in FIG. 2A, thesteerable probe has a tubular member 201 with an axial bore 205. Thetubular member 201 is preferably made of a compressible substance toreduce the harm that may be caused by any inadvertent contact with anyintraocular structures. Thus, tubular member 201 may be composed of manydifferent types of materials, such as a variety of polymeric materials.Preferably, the material used for tubular member 201 should have theproperties of being resilient, being very flexible, having lowhysteresis, and that it can be precisely extruded. In one embodiment,tubular member 201 is composed from a PEBAX polymer, which is made frompolyether block amides, a biocompatible, plasticizer free thermoplasticelastomer that has such properties. However, as PEBAX has proveddifficult to secure with adhesives, PVC tubing, which has similarproperties, is presently most preferred for tubular member 201.

An implement, for example a surgical or diagnostic tool, is situated ator near the distal end 204 of the tubular member 201. In the case of asteerable laser probe, optical fiber 202 is inserted lengthwise throughthe axial bore 205 of the tubular member 201 to provide a laserphotocoagulator at distal end 204 (and in such a case, it will beunderstood that the distal end of the optical fiber, through which laserlight is delivered, acts as the “implement”). Optical fiber 202 istypically comprised of a silica core with cladding and is preferablyfurther coated with polyimide plastic coating to increase its resistanceto breakage. (While this specification generally uses the term “opticalfiber” to describe an optical conduit component in various embodiments,it will be understood that the term is intended to encompass any type ofconduit, waveguide or fiber for transmitting electromagnetic energy, forexample, multimode and singlemode fibers, as well as fiber optic cablescomprised of a plurality of fibers.) Optical fiber 202 is also flexible.A wire member, referred to in this embodiment as a guide wire (203) isalso inserted lengthwise through the axial bore 205 of the tubularmember 201. The guide wire 203 is affixed to the tubular member at ornear distal end 204. The proximal ends of both the guide wire 203 andthe optical fiber 202 extend beyond the proximal end of the tubularmember 201. Preferably, the guide wire 203 is provided in a form suchthat it is normally in a straight conformation. However, the guide wire203 is flexible so that when a bending force is applied to it, the wire203 will curvedly deform and have a curvature in accordance with theforce. Once the force is removed, the guide wire 203 will tend to springback to its normal straight conformation.

In the embodiment described above, guide wire 203 is made of nitinol.However, guide wire 203 may be any type of wire member, that is, anygenerally lengthwise-extended structure made of any material that isbendably flexible and resistant to tensile and compressive stress, thatcan be formed into a wire or cable shape. In some applications, it isdesirable that this material exhibit the property of tending to returnto a first conformation after being deformed from that conformation, butthis property is not essential in other applications (in someapplications, a degree of hysteresis may in fact be desirable). Aplastic optical fiber (or other similar fiber optic) can bend at thedistal tip and can also serve as such a guide wire. The advantage of thefiber optic is that it can also be used to bring light into the eye.This would provide a lighted laser probe. Treatments such as shaping thedistal end of the fiber optic could help control the distribution oflight emanating from the tip of the illumination fiber. Thus, theangular spread of light leaving the fiber optic delivering light couldbe different from the cone angle of laser light leaving the laser fiberoptic. A fiber delivering light can be of the same composition as thelaser fiber, namely silica fiber with polyimide cladding. Silica fiberwith polyamide cladding costs much more per meter than does plasticoptical fiber, and for simple delivery of light plastic optical fibersuffices. For purposes of this disclosure, and the claims, the term“wire member” is defined to include any structure as discussed in thisparagraph.

The steering capability of the present invention is shown in FIGS. 2B-C.The guide wire 203 can slidably move with respect to the tubular member201 in the axial direction when there is a force upon the guide wire 203in the axial direction at the proximal end 206 of the wire 203. However,as explained above, the guide wire 203 is also fixed at or near thedistal end 204 of tubular member 201. The slidable movement of the guidewire 203 at its proximal end 206 while being fixed at or near its distalend 204, held within a flexible housing, and with its longitudinal axisradially offset from the longitudinal axis of said housing, will causethe guide wire to curvedly deform such that the guide wire 203 becomessituated at either the inner or outer circumference of the bend when theforce is applied—the inner circumference (which is shorter), when theforce (207 in FIG. 2B) is to retract the guide wire 203, and the outercircumference (with is longer), when the force (208 in FIG. 2C) is toextend the guide wire 203.

To examine this action in further detail, we will refer again to FIG.2B. In that figure, the force 207 that is pulling the guide wire 203 atthe proximal end 206 causes the wire 203 to slidably move. But becausethe guide wire 203 is also fixed at or near distal end 204, the wire 203in turn curvedly deforms in a transverse direction 209. Because thetubular member 201, and optical fiber 202 is flexible along its axis, itwill curvedly deform along with the wire 203 in the transverse direction209 so as to make the guide wire (which is radially offset within thebore 205) assume a position on the inner circumference 211 of the curveddeformation. As shown in FIG. 2C, when a force 208 that pushes the guidewire 203 in the axial direction is exerted, so as to extend the guidewire 203 away axially from the proximate end of the device, the guidewire 203, along with the tubular member 201, will curvedly deform in theopposite transverse direction 210, so as to make the guide wire 203assume a position on the outer circumference 212 of the curveddeformation.

Thus, by exerting an axial force on wire 203, the slidable movement ofthe wire 203, coupled with its affixation at the distal end 204, createsa controllable transverse curved deformation of the guide wire 203 andtubular member 201. This curved deformation creates a range of steerablemotion for distal end 204—wherein the precise location of the distal end204 depends on the magnitude and direction of the forces 207 and 208.Furthermore, the proximal end of tubular member 201 may be kept straightwhile its distal end is being laterally moved. If inserted, for examplethrough a cannula, the assembly may be rotated axially within thecannula (with the distal end also movable transversely, as above), toprovide an additional degree of control to the instrument (and inaddition, the distance of insertion can also be varied). Any implement,in one embodiment a laser photocoagulator, disposed at the distal end204 of the instrument will be provided with a corresponding range ofsteerable motion.

FIGS. 3A-B are cross-sectional views of two embodiments of a probe ofthe present invention taken perpendicularly to the axis of tubularmember 301 (similar to tubular member 201 of FIG. 2A). (It is noted thatin this disclosure, the least two significant digits of referencenumerals are used to denote functionally corresponding but notnecessarily identical structures as among various drawings. Thesestructures will be differentiated by the leading numeral in the“hundreds” place, and/or alternatively, by a trailing letter (“e”, “f”,“g” etc.) after the two least significant digits; thus, tubular member301 in FIG. 3A functionally corresponds to tubular member 201 in FIG.2A, and so forth.)

In FIG. 3A, tubular member 301 has two axial bores 314 and 325. Axialbores 324 (shown here as the larger of the two bores) and 325 (shownhere as the smaller of the two bores) are off-center bores whose axesare (in one embodiment) parallel to, but radially offset from, thecentral axis of tubular member 301. In one embodiment, optical fiber 302(similar to optical fiber 202 in FIG. 2A) extends lengthwise throughaxial bore 324, while guide wire 303 (similar to guide wire 203 in FIG.2A) extends lengthwise through axial bore 325. In a preferredembodiment, guide wire 303 is made of nitinol and has a diameter ofabout 0.005 inches. In order to house a guide wire of such diameter,axial bore 325 has preferably a diameter of about 0.006 inches. Opticalfiber having a core diameter of from about [50] microns to about 250microns may be used. The optical fiber employed in this embodiment tocomprise optical fiber 302 has a nominal diameter with cladding of about100 to 120 microns, and the polyimide coating adds about 20 additionalmicrons to the diameter. Thus, the total diameter of this optical fiberapproaches 150 microns, or approximately 0.006 inches. In order to housesuch an optical fiber, axial bore 324 preferably has a diameter of about0.007 inches.

A probe in accordance with the present invention, in numerousembodiments, can be used in vitrectomy surgery. Vitrectomy surgery canbe performed with various sizes of instruments, for example, 20 gaugeinstruments, or 0.9 millimeter diameter, 23 gauge instruments, or 0.62millimeter diameter, or 25 gauge instruments, or 0.5 millimeterdiameter, or even smaller gauge instruments down to a diameter of about0.25 mm. This means, for example, that in surgeries using 20 gaugeinstruments, the diameter of the tubular member cannot exceed about 0.9millimeters. The twin axial bore configuration shown in FIG. 3Afunctions well for 20 and 23 gauge instruments, but for 25 gaugeinstruments, the diameter of the tubular member is too small for thetwin bore configuration to be manufactured easily. This is addressed inthe alternate embodiment shown in FIG. 3B.

In FIG. 3B, there is a single axial bore 305 b in the tubular member 301b. Axial bore 305 b and tubular member 301 b are (in this embodiment)co-axial. Axial bore 305 b is of a sufficient diameter so that both theguide wire, as shown in cross section 303 b and the optical fiber, asshown in cross section 302 b can extend lengthwise in the bore 305 b.Note that in this configuration, the axes of both the guide wire and theoptical fiber are parallel to the axis of the tubular member 301 b butthe axes do not coincide, and most particularly, the axis of guide wire303 b is radially offset from the axis of the tubular member, eventhough it runs within a bore that is coaxial with the tubular member.Thus, the mechanics of transverse curved deformation are qualitativelysimilar to those applicable to the dual bore embodiment when forces areapplied to extend or retract the guide wire 303 b relative to tubularmember 301 b. Accordingly, the single-bore embodiment of FIG. 3Bdisplays comparable steerable behavior to the dual-bore embodiment ofFIG. 3A.

FIG. 4 is a side elevational view of an embodiment of a probe inaccordance with the foregoing, coupled with an embodiment of a handlefor the probe. Tubular member 401 (similar to tubular member 201 in FIG.2A) is placed at the distal end 417 of a segment of rigid hollow tubing416, preferably stainless steel hypodermic tubing, whose proximal end isin turn attached to a handle or boss 418. The rigid hollow tubing 416can vary in diameter as required by the size of the surgical instrumentsused. Preferably, the diameter of the tubing 416 will correspond to thediameters of the cannulae or incisions employed in the varioussurgeries, for example vitrectomy surgery. The boss 418 also has anopening in the longitudinal (axial) direction (not visible in thisdrawing) from its distal end 420 to proximal end 419. An optical fiber402 (similar to optical fiber 202 in FIG. 2A) and guide wire 403(similar to guide wire 203 in FIG. 2A, but within the other componentsand therefore not shown in this drawing) run axially through tubularmember 401, and extend past the proximal end 419 of the rigid hollowtubing 416, into the body of the boss 418 through its distal opening at420. The optical fiber preferably extends past the proximal end 419 ofthe boss 418 so that it can be connected to an external laser source.Once outside the boss 418, the optical fiber may be covered by jacket413. Guide wire 403, on the other hand, terminates within the boss 418and is connected to an actuator 414 (not shown) internal to boss 418,which is controlled through finger pad 415. Movement of the finger pad415 moves guide wire 403 through actuator 414, which causes the steeringoperation in this steerable probe embodiment. The structure of theactuator is the subject of several alternate designs, which are furtherdescribed below with reference to FIGS. 5A-H.

First Actuator Embodiment

FIGS. 5A-B are side sectional views of what is currently the mostpreferred embodiment of the probe and handle combination as discussedabove with respect to FIG. 4, showing its actuator structure 514. FIG.5A shows that embodiment with finger pad 515 in a forward position, andFIG. 5B shows that embodiment with finger pad 515 in a rearward,retracted position. Finger pad 515 forms the top of a threaded shaft540, which screws into a base receiving element 541. Base receivingelement 541 has a transverse hole 544 through which housing 521 passes.Threaded shaft 540 is tightened in receiving element 541 in the mannerof a set screw, so as to secure housing 521 to the assembly comprisingreceiving element 541, threaded shaft 540 and finger pad 515. Receivingelement 541 is set in recess 523 so that it may slidably move fore andaft longitudinally within boss 518. The size of opening 523 is such thatit limits the excursion of the finger pad mechanism so that harm to thelaser fiber 502 will not occur. Housing 521 slidably fits into boresections of axial bore 527 through boss 518, at the proximal and distalends of recess 523. Sliding finger pad 515 forward and backward withrespect to boss 518 moves housing 521 forward and backward within saidbore sections, (correspondingly serving to extend and retract guide wire503 as will be addressed below with respect to housing 521).

Housing 521 is shown in detail, in axial cross-section, in FIG. 5C, andin radial cross section in FIG. 5D. Outer housing tubing 532 ispreferably 21 gauge extra thin wall stainless steel tubing, whichtypically has an inner diameter of 0.025 inches. Contained within thisis inner housing tubing 531, which preferably is 25 gauge stainlesssteel tubing, which has an outside diameter of 0.020 inches. Wedgedbetween the space caused by eccentric placement of 531 is guide wire503. Additionally guide wire 503 is secured in place with adhesive 535.As shown in FIG. 5C, guide wire 503 terminates within housing 521. Laserfiber 502 is threaded lengthwise through inner housing tubing 531. Inuse, movement of the outer housing tubing 532 causes associated movementof guide wire 503 and inner housing tubing 531. The laser fiber 502coursing through the center of inner housing tubing 531 is not attachedto the tubing structure of housing 521, and not affected by the movementof that tubing structure. Thus, moving finger pad 415 fore and aft inrecess 523 will extend and retract guide wire 503 relative to theproximal end 517 of tubular member 501, but will do so without affectingor putting any stress on laser fiber 502.

Second Actuator Embodiment

FIGS. 5E-F are side sectional views of an alternate embodiment of anactuator assembly for a probe and handle combination as discussed abovewith respect to FIG. 4. FIG. 5E shows the side sectional view of theprobe and handle of such an embodiment at a first position. Axial bore527 e through the boss 518 e is now visible. Also visible is a recess523 e in the boss 518 e towards the distal end 520 e of boss 518 e. Therecess 523 e is used to accommodate actuator mechanism 514 e. It issimilar to recess 523 in FIG. 5A, but longer at the top to accommodateangular movement of the finger pad 515 e. Axial bore 527 e provides boresections at either end of recess 523 e. Actuator mechanism 514 e has aninput point n the form of finger pad 515 e, through threaded shaft 540 ewhich screws into receiving element 541 e, which in turn has a fulcrumpoint 542 e at its base. Housing 521 e (similar in structure to housing521 in FIG. 5A) passes through receiving element 541 e throughtransverse hole 544 e and is held in place by threaded shaft 540 e bymeans of a detent (not shown) in housing 521 e, which allows saidhousing to move fore and aft in the bore sections at either end ofrecess 523 e. Thus, receiving element 541 e is movably affixed to theboss 518 e at fulcrum point 542 e, so that receiving element 541 e,threaded shaft 540 e and finger pad 515 e can be rocked fore and aftwith respect to fulcrum point 542 e in a plane approximately alignedwith the distal probe portion of the instrument. Since housing 521 e isdriven by this assembly at a point intermediate the input element(finger pad 515 e) and the fulcrum point 542 e, a second class lever isthereby provided to control housing 521 e and correspondingly, guidewire 503 e. This way, when an input force is applied to finger pad 515e, such as when the surgeon pushes or pulls the finger pad 515 e,receiving element 514 e will move rotationally in the correspondingdirection about the fulcrum point 542 e, causing housing 521 e to movefore and aft in the bore sections at either end of recess 523 e, therebymoving guide wire 503 e fore and aft relative to boss 518 e andultimately the proximal end of tubular member 501 e. Guide wire 503 emust be moved by only about +/−½ mm to flex the tip of the instrument,and thus, the amount of angular movement of the lever required to flexthe tip is small.

Third Actuator Embodiment

In yet another actuator embodiment, as shown in FIGS. 5G and H, threadedshaft 540 g is used to directly secure guide wire 503 g to receivingelement 541 g. Guide wire 503 g passes through a first transverse hole544 g in receiving element 541 g and is held in place by threaded shaft540 g, acting as a set screw, while laser fiber 502 g passes freelywithout attachment through a second transverse opening, transversepassage 545 g, in receiving element 541 g. Actuating this assemblythrough finger pad 515 g again, as described with respect to FIG. 5E,rocks receiving element 541 g as a second class lever with respect tofulcrum point 542 g, thereby extending and retracting guide wire 503 gto cause the bending action of tubular member 501 g. Again, only a smallrocking movement is required to flex the tip. In this embodiment, Guidewire 503 g terminates inside boss 518 g at proximal point 543 g.Transverse passage 545 g through receiving element 541 g allows theoptical fiber 502 g to thread through and extend past the actuatorassembly 514 g, exit the boss 518 g at the proximal end 519 g andconnect to an external laser source (not shown). This way, optical fiber502 g is not significantly moved or disturbed when the receiving element541 g rotates about the fulcrum point 542 g.

A further feature is provided with respect to this third actuatorembodiment. Due to the length of the guide wire 503 g from the distalend of the boss 518 g, at 520 g, to the point of affixation to receivingmember 541 g, guide wire 503 g may buckle in this span. This creates aproblem because if guide wire 503 g buckles in this span, then thelevered rotation of receiving element 541 g will not cause the guidewire 503 g to slidably extend or retract, and in turn the guide wire 503g will not curvedly deform the tubular member 50 g as desired. Thesolution to this problem is to house the guide wire 503 g in hollowreinforcement tubing 531. The reinforcement tubing 531 is also held bycompression by threaded shaft 540 g, acting as a set screw in receivingelement 541 g. Because curvedly deforming the guide wire 503 g withintubular member 50 g by the operation of actuator 414 g does not requiremuch force, there is no significant bending moment in the reinforcementtubing 531.

In each of the above-described actuation embodiments (referring to FIG.5A by way of example, though the following discussion applies equally toFIGS. 5E and 5G), causing guide wire 503 to extend or retract relativeto boss 518 serves to actuate the bending motion of tubular member 501.Since the guide wire 503 is affixed to the tubular member 501 at or nearthe distal end of tubular member 501, and tubular member 501 is itselfaffixed to rigid hollow tubing 516, the tubular member 501 cannot slidealong with the guide wire 503. Instead, as discussed with respect to theembodiment shown in FIGS. 2A and 2B, the extension or retraction ofguide wire 503 in these embodiments cause the tubular member 501 andguide wire 503 within it to curvedly deform transversely, such that theguide wire 503 is situated on the inside circumference of the curvedlydeformed tubular member when retracted and on the outside circumferencewhen extended.

As shown in FIG. 5B (and, correspondingly in FIGS. 5F and 5H), whenfinger pad 515 is pulled backwards, the guide wire 503 is retractedrelative to tubular member 501. As can be seen in FIG. 5B (and,correspondingly in FIGS. 5F and 5H), by comparing its position with theposition of optical fiber 502, the axis of the guide wire 503 isdisposed so as to be offset radially, toward the top of the drawingrelative to the longitudinal axis of the tubular member 501.Consequently, the distal end of the tubular member 501 curves upward inresponse to being so retracted (placing it on the inside, shortercircumference of the now curved tubular member). Similarly, pushing thefinger pad 515 forward will in turn cause the distal end of the tubularmember 501 to curve downward. It should also be noted that releasingfinger pad 515 in any of the illustrated embodiments after the probe hasbeen actuated causes it to return to the position corresponding to thenormal configuration of guide wire 503.

Because a surgical or diagnostic instrument, such as the output end of alaser photocoagulator, is situated at or near the distal end of thetubular member 501, the instrument can be directed as the tubular memberis steered as described above. As configured in this embodiment, thedistal end of the tubular member 501 is capable of curving more than 100degrees in each direction, allowing nearly complete laserphotocoagulation of the retina by placing the instrument through onesclerotomy opening in the eye. Because (in this particular embodiment)the guide wire 503 was selected to be statically straight such that itwill only deform when a force is applied to it, releasing the finger pad515 causes the guide wire 503 and in turn the tubular member 501automatically to straighten. This is advantageous because the naturalstraight position can be assumed when the instrument first enters theeye, as insertion of an object is easier if done normal to the surface.Also if a cannula system is used during the surgery, the steerable probeis more easily inserted if straight because the cannula is straight.Thus, when the surgeon is first inserting the steerable probe of thepresent invention into the eye or a cannula, he need not exert anyforces upon finger pad 515. After the tubular member 501 is insertedinto the eye, a surgeon, by operating finger pad 515, can steerablycurve the tubular member 501 to avoid obstruction internal in the eye asthe crystalline lens, and more precisely position the instrument.

FIG. 6 shows another embodiment of a probe in accordance with thepresent invention. Instead of a dynamically steerable probe describedabove, the embodiment shown in FIG. 6 is a statically curved probe. Likethe steerable probe, the statically curved probe has tubular member 601having an axial bore 605 for housing a guide wire 603 and an implement(in this case the end of optical fiber 602) is attached to the distalend 604 of the tubular member 601. In the case of a curved laser probe,an optical fiber 602 is inserted lengthwise through the axial bore 605of the tubular member 601 to provide a laser photocoagulator at distalend 604. Unlike the steerable probe however, the guide wire 603 is notstatically straight but rather is trained to be curved. Because thetubular member 601 and optical fiber 602 are both flexible, they willalso conform to this curvature. To avoid rotation by the guide wire 603inside axial bore 605, the guide wire 603 is affixed to tubular member601 at both distal end 604 and proximal end 606. The radius of curvatureis large enough so that the curved probe can pass through a straightcannula with ease, thus overcoming limitations in the prior art. Thepreferred range of this radius is from approximately 15 mm toapproximately 45 mm. The radius of curvature of the tubular member 601in this embodiment is approximately 18 mm.

FIG. 7 is a side sectional view of the probe embodiment described withrespect to FIG. 6, coupled with a corresponding handle. The tubularmember 601 containing the guide wire 603 (not shown in FIG. 7) andoptical fiber 602 in the axial bore 605 (not shown) is attached at itsproximal end 604 to the distal end of rigid hollow tubing 716,preferably stainless steel hypodermic tubing. The proximal end 720 ofthe hollow tubing 716 is in turn attached to a handle or boss 718. Therigid hollow tubing 716 can vary in diameter as required by the size ofthe surgical instruments used, and the diameter of the hollow tubing 716corresponds to the diameters of the cannulae or incisions employed inthe applicable surgical practice, for example vitrectomy surgery usingvarious gauge equipment. The boss 718 also has an axial bore 727 in thelongitudinal direction, running from its distal end 720 to proximal end719. The optical fiber 602 extends through this bore past the proximalend 606 of the tubular member 601, through the hollow tubing 716, intoand through the body of the boss 718 through its bore 727. The opticalfiber 602 preferably extends past the proximal end 719 of the boss 718so that it can be connected to an external laser source (not shown).Once outside the boss 718, the optical fiber 602 may be covered byjacket 713. The handle thus described allows the easy insertion of theprobe through an incision or cannula. Once inserted, the probe assumesit naturally curved state, in which it can be selectively rotated intomany positions, with better reach than a fully rigid probe.

Those skilled in the art will appreciate, upon reading the foregoing,that a probe in accordance with any of the embodiments of the presentinvention overcomes the limitations of the prior art. First, a probe inaccordance with the present invention, either statically curved ordynamically steerably curved, can curve around internal obstructionssuch as the crystalline lens of the eye and allow the probe to havedirect lines of access to all peripheral areas of the internal wall ofthe eye. Second, in case where the probe is used as a laserphotocoagulator, by allowing the probe to have direct lines of access,the laser output emitting from the instrument can be directed to impingeupon the coagulation site of the eye at a normal angle of incidence,thus maximizing the intensity of the laser energy at the coagulationsite. Third, unlike prior art probes that employ a rigid metal outersleeve, the probes of the present invention employ a tubular membercomposed of a biocompatible, plasticizer free thermoplastic material,which may more safely be moved near delicate internal structures of theeye.

In addition, steerable and curved probes as described herein may bereadily used and adapted for use in other types of surgical anddiagnostic procedures, such as cardiovascular, gastrointestinal andother types of surgery and diagnostic methods in which it an instrumentis introduced or threaded trough an opening or passageway and amechanism is desirable to direct or steer the instrument after itsintroduction.

The foregoing summary, drawings, and detailed descriptions describevarious embodiments of the invention and the principles by which theinvention operates, and show the advantages that the invention providesover previous solutions. It is believed that the invention has beenexplained in sufficient detail to enable persons of ordinary skill inthe field who study this disclosure to practice the techniques shown, aswell as other variations and embodiments within the spirit of theinvention that suit their individual needs. Accordingly, the specificfeatures of the invention are not intended to limit the scope of theinvention, as defined in the following claims.

1. A steerable probe comprising: a) a flexible tubular member providinga position for holding an implement at or near the distal end thereof,said flexible tubular member being flexible along its longitudinal axisand having at least one longitudinal axial bore extending from itsproximal end to its distal end; b) a wire member extending lengthwisethrough the length of said at least one axial bore, wherein i. said wiremember has the properties of being flexible in a bending mode andresistant to tensile and compressive stress, ii. said wire member isdisposed within said at least one axial bore such that the longitudinalaxis of said wire member is substantially parallel to but radiallyoffset from the longitudinal axis of said flexible tubular member, iii.the distal end of said wire member is securely affixed to or near thedistal end of said flexible tubular member; and iv. the proximal end ofsaid wire member is slidably movable in the axial direction with respectto said at least one axial bore, so as to be extendable and retractablerelative to said at least one axial bore, wherein said slidablemovement, radially offset disposition and affixation causes said wiremember to curvedly deform so as to be situated on the innercircumference of said flexible tubular member when said slidablemovement acts to retract said wire member relative to said at least oneaxial bore, and to be situated on the outer circumference of saidflexible tubular member when said slidable movement acts to extend saidwire member relative to said at least one axial bore.
 2. A probeassembly comprising a) the steerable probe of claim 1, and b) a handlecomprising a proximal boss and a rigid tubular member at the distal endthereof, said rigid tubular member being attached at its distal end tothe proximal end of said probe, wherein, the wire member internal tosaid steerable probe extends through said rigid tubular member and intosaid boss.
 3. The probe assembly of claim 2 further comprising anactuator mounted within said boss, said actuator being attached to saidwire member and being operable to extend and retract said wire memberwith respect to the at least one axial bore internal to said probe. 4.The probe assembly of claim 3 wherein said actuator comprises amechanical element secured to a section of said wire element andslidable in a space provided within said boss in a direction generallyaligned with the axis of said axial bore.
 5. The probe assembly of claim3 wherein said actuator comprises a class 2 lever having a fulcrum atits distal end, said fulcrum being affixed to said boss such that saidlever is movable in a plane approximately aligned with said probe, aninput location for movement of said lever at its proximal end, and anattachment to said wire member at a point intermediate said inputlocation and said fulcrum.
 6. The probe assembly of claim 3 wherein saidactuator is activated through a finger pad protruding externally to saidboss.
 7. A probe in accordance with claim 1 further comprising asurgical or diagnostic implement provided at the distal end thereof. 8.A probe in accordance with claim 7, wherein said surgical or diagnosticimplement is an optical fiber adapted to emit light from the distal endof said probe.
 9. A probe assembly in accordance with claim 2, furthercomprising a surgical or diagnostic implement provided at the distal endthereof.
 10. A probe assembly in accordance with claim 9, wherein saidsurgical or diagnostic instrument is an optical fiber adapted to emitlight from the distal end of the flexible tubular member of said probeassembly.
 11. A steerable laser photocoagulator comprising a) a probeassembly in accordance with claim 3, b) an optical fiber, positioned insaid probe assembly to have a distal terminus at or near the distal endof said flexible tubular member, disposed at or near said distal end soas to be able to output light from said distal end, and extendinglongitudinally through said flexible tubular member and said rigidtubular member and at least into said boss, and c) a laser light sourcecoupled to the proximal end of said optical fiber.
 12. A steerable laserphotocoagulator in accordance with claim 11 wherein, within said boss,said optical fiber traverses said actuator by passing through a passagemechanically isolated from the movement of said actuator.
 13. Thesteerable laser photocoagulator of claim 12 where said passage is apassage through the structure of said actuator.
 14. A probe inaccordance with claim 1 wherein said wire member has the furtherproperty of tending to return to a first lengthwise conformation afterbeing bendably deformed therefrom.
 15. A probe assembly in accordancewith claim 14 wherein said wire member comprises a nitinol wire.
 16. Aprobe in accordance with claim 1 wherein said wire member is composed ofa material that will transmit light illumination.
 17. A probe inaccordance with claim 16 wherein said wire member comprises a plasticoptical fiber.
 18. A probe in accordance with claim 8, wherein saidoptical fiber comprises silica optical fiber.
 19. A probe in accordancewith claim 18, wherein said silica optical fiber is cladded and the corediameter of said silica optical fiber including cladding is in the rangeof about [50] to 250 microns.
 20. A probe in accordance with claim 19wherein the core diameter of said silica optical fiber includingcladding is about 100 to 120 microns.
 21. A probe in accordance withclaim 18, wherein said optical fiber has an exterior coating.
 22. Aprobe in accordance with claim 21 wherein said exterior coating is madeof a composition comprising polyimide.
 23. A probe in accordance withclaim 1 comprising at least two longitudinal axial bores, the first ofwhich carries said wire member and the second of which is incommunication with a surgical or diagnostic implement provided at thedistal end of said probe.
 24. A probe in accordance with claim 23wherein said second bore carries an optical fiber.
 25. A probe inaccordance with claim 22, further comprising at least two longitudinalaxial bores, the first of which carries said wire member and the secondof which is in carries said optical fiber, wherein said wire member hasa diameter of about 0.005 inches, the first said longitudinal axial borehas a diameter of about 0.006 inches and the second said longitudinalaxial bore has a diameter of about 0.007 inches.
 26. The probe of claim1, wherein said flexible tubular member has a range in diameter fromabout 0.25 millimeters to about 0.9 millimeters.
 27. The probe of claim1, wherein said flexible tubular member is made of a compositioncomprising a polymer.
 28. The probe of claim 27 wherein said polymercomprises PVC.
 29. The probe of claim 27, wherein said polymer comprisespolyether block amides.
 30. The probe assembly of claim 5 wherein saidclass 2 lever is affixed to said wire element with a compressivefastener and further comprising a housing surrounding said wire member,said housing comprising a length of reinforcement tubing between saidlever and the distal exit point of said wire member from said boss. 31.The probe assembly of claim 30, wherein said reinforcement tubing isalso secured to said class 2 lever by said compressive fastener.
 32. Aflexible probe comprising: a) a flexible tubular member providing aposition for holding an implement at or near the distal end thereof,said flexible tubular member being flexible along its longitudinal axisand having at least one longitudinal axial bore extending from itsproximal end to its distal end; b) a wire member extending lengthwisethrough the length of said at least one axial bore, wherein i. said wiremember has a property whereby said wire member tends to return to afirst lengthwise conformation after being deformed therefrom, ii. thelongitudinal axis of said wire member is substantially parallel to saidlongitudinal axis of said flexible tubular member, iii. the distal endof said wire member is securely affixed to or near the distal end ofsaid flexible tubular member; and iv. the proximal end of said wiremember is securely affixed to or near the proximal end of said flexibletubular member, wherein said tubular member may be deformed from saidfirst lengthwise conformation in one step of a surgical or diagnosticprocedure and then without intervention return to said first lengthwiseconformation.
 33. A flexible probe in accordance with claim 32 whereinsaid first lengthwise conformation is a curved conformation, saidtubular member may be deformed from said straight conformation forinsertion through an incision or cannula, and will resume said firstlengthwise curved conformation after passing beyond said incision orcannula upon such insertion.
 34. A flexible probe in accordance withclaim 33 wherein the radius of said curved conformation is in the rangeof 15-45 mm.
 35. The flexible probe of claim 34 wherein said radius isapproximately 18 mm.
 36. A flexible probe assembly comprising: a) aflexible probe in accordance with claim 32, and b) a handle comprising aproximal boss and a rigid tubular member at the distal end thereof, saidrigid tubular body being attached at its distal end to the proximal endof said probe.
 37. A method for performing a surgical or diagnosticprocedure using a probe assembly in accordance with claim 2, comprisinga) inserting said probe assembly through an incision or cannula, b)actuating said wire member so as to induce the desired curvature of saidprobe, and c) rotating said probe about its longitudinal axis so as topoint the distal end of said probe in the desired direction.
 38. Amethod for performing a surgical or diagnostic procedure using a probeassembly in accordance with claim 33, comprising a) inserting said probeassembly through an incision or cannula to a sufficient insertiondistance such that the flexible tubular member thereof assumes saidfirst longitudinal curved conformation, and b) rotating said probe aboutits longitudinal axis so as to point the distal end of said probe in thedesired direction.
 39. A method for performing a surgical or diagnosticprocedure using a probe assembly in accordance with claim 3, wherein thefirst lengthwise conformation of said wire member is a straightconformation, said method comprising (a) inserting said probe andoperating said probe in a curved configuration by actuating the linkagerecited in claim 3, and (b) later returning said probe to a straightconfiguration by releasing said linkage.